The present invention relates to a device for feeding parts to be mounted to at least one upper or lower tool of a mounting machine for machining or further processing the parts to be mounted whereby the upper and lower tools are movable relative to one another between a working position and a rest position and the parts to be mounted are fed to the respective tool via a feed channel with the aid of a push rod.
Such devices for feeding parts to be mounted are known in general. They are especially used in connection with machines for mounting rivets, snap closures, etc. For example, a device of the aforementioned kind for feeding parts to be mounted is known from German Offenlegungsschrift 42 25 264. According to this disclosure, a spring-loaded lever with a projecting part is arranged at a feed path located at a lift-controlled upper tool and is forced by a downward movement of the upper stamp against the spring force into a rearward position. This movement entrains a carriage into a retracted position. The carriage has connected thereto push rods. When the lift-controlled upper stamp is moved into its upper position, the lever due to the spring loading is pulled into a forward position and moves the carriage also into a forward position. The push rods then impact the parts to be mounted, located within the feed channel, and guide them to the upper and/or lower tool, respectively, the holding device arranged thereat. In order to provide sufficient time for the insertion of parts to be mounted into the feed channels, the feed push rods are returned into a position that is far behind the location of introduction of the parts into the feed channel. Thus, due to the high return speed of the push rods a considerable impacting speed of the push rod onto the parts inserted occurs. Due to this impact the parts can be damaged in an undesirable manner and the device produces large amount of discard. Furthermore, the masses must travel a long distance within a very short period of time so that a large amount of energy is required for operating the device. For example, if it is desired to shorten the travel path with a corresponding arrangement of the push rod, the insertion time is automatically shortened. Furthermore, a large number of components must be positioned relative to one another, aligned, and adjusted. Also, there is no option for controlling or simply varying of the insertion time. Moreover, due to certain switch arrangements the feeding device is switched off when the forward movement of the push rod is obstructed. Due to the high acceleration forces, however, a considerable obstructing force is required to cause a switching off. Slightly deformed parts etc. will still be fed to the tools. An adjustment of this reaction force is also not possible.
Due to the masses being moved at high velocities, the known devices for feeding parts to be mounted require a considerable amount of maintenance and are subject to great wear.
It is therefore an object of the present invention to improve a device for feeding parts to be mounted of the aforementioned kind such that the construction is simplified and the servicing expenditure, the wear susceptibility, and the requirements for adjustment and alignment are reduced. Variability of the insertion time should also be provided with simple means.